... it has been possible to create huge mappings in the vmalloc area at
runtime, and as part of this existing intermediate levels of table my be
removed and freed.

It's possible for the ptdump code to race with this, and continue to
walk tables which have been freed (and potentially poisoned or
reallocated). As a result of this, the ptdump code may dereference bogus
addresses, which could be fatal.

Since huge-vmap is a TLB and memory optimization, we can disable it when
the runtime ptdump code is in use to avoid this problem.